The present invention relates to a resistor circuit, an interface circuit including a resistor circuit, and an electronic instrument.
JP-A-2003-270299 discloses related-art technology in which a terminating resistor for impedance matching is provided in a receiver circuit, for example. Such a terminating resistor is generally provided as an external part of an integrated circuit (IC) device on a circuit board or the like on which the integrated circuit device is mounted.
However, when incorporating a high-speed serial interface circuit in a driver IC or the like, it is difficult to externally provide such a terminating resistor due to limitations on mounting of the driver IC.
A serial interface circuit conforming to Universal Serial Bus (USB), IEEE1394, or the like is known as a high-speed serial interface circuit. Such a serial interface circuit may include a terminating resistor, but is not designed taking into account the effects of interconnect parasitic resistance and the like. A method may be considered in which a terminating resistor is accurately adjusted using a fuse element in order to substantially disregard the effects of such a parasitic resistance.
However, this method has a problem in that the number of fuse blowing steps increases along with an increase in the number of resistor stages, whereby it takes time to adjust the resistance value.